One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(6,7)(9,10)(11,16)(12,17)(13,18)(14,15)(19,23)(20,24)(21,22)(25,26,31,34)(27,35,37,32)(28,38,39,29)(30,33,36,40)(1,2,5,4)(3,7,8,6)(9,11,15,12)(10,16,14,17)(13,20,21,19)(18,24,22,23)(25,27,31,37)(26,32,34,35)(28,33,39,40)(29,36,38,30)(1,3,5,8)(2,6,4,7)(10,14)(11,12)(13,21)(23,24)(28,39)(29,38)(30,36)(33,40)(1,4,5,2)(3,7,8,6)(9,12,15,11)(10,17,14,16)(13,19,21,20)(18,23,22,24)(25,28,31,39)(26,29,34,38)(27,33,37,40)(30,32,36,35)(9,13,15,21)(10,18,14,22)(11,19,12,20)(16,23,17,24)(25,29)(26,28)(27,36)(30,37)(31,38)(32,33)(34,39)(35,40)(9,14,15,10)(11,17,12,16)(13,22,21,18)(19,24,20,23)(25,30,31,36)(26,33,34,40)(27,29,37,38)(28,32,39,35)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.